COVID‐19 in Morocco's region: Observational study of prevalence in symptomatic adults using the PANBIOS® rapid antigen test September 2021

Abstract Background Rapid antigen tests have emerged to deal with the COVID‐19 pandemic. Rapid diagnosis of SARS‐CoV‐2 infection is essential to reduce the spread of the disease. The aim of this study was to estimate the prevalence of COVID‐19 infection and test the sensitivity and specificity in Temara‐Skhirat in symptomatic adults through PANBIOS® test. Methods A prospective observational study was conducted in mid‐September 2021. Two investigators conducted data collection from symptomatic adult patients. The diagnostic performance of the PANBIOS®, and the PCR was assessed to calculate sensitivity and the specificity. Results Among 206 symptomatic participants, the mean age was 38 ± 12 years, and the majority were women (59%). In our population, 80% had benefited from the anti‐COVID vaccine. The median duration of symptoms was 4 days; the most common symptoms were fatigue (62%), headache (52%), fever (48%), cough (34%), loss of smell (25%), loss of taste (24%), and sore throat (22%). Results revealed 23% of cases tested positive with PANBIOS® test versus 30% with the PCR test. The calculated medical decision between PCR versus PANBIOS® test showed high specificity of 95.7% and a sensitivity of 69.4%. There was concordance between the PANBIOS® test and the PCR. Conclusion The prevalence tested remain high, and the sensitivity and specificity of the PANBIOS® versus PCR test are similar to other literatures and close to value described in WHO recommendations. PANBIOS® is a useful test for controlling the spread of COVID‐19 allowing identification of active infection.


| INTRODUCTION
Since first discovered in December 2019, the global pandemic of coronavirus disease 2019  caused by the novel coronavirus (SARS-CoV-2) poses a serious threat to human life and health. 1 Morocco, like other countries in the world, has experienced the ups and downs of the coronavirus disease "COVID-19," which has caused an unprecedented health crisis. If this pandemic has highlighted points of vulnerability, it has also made it possible to highlight the potentialities that this country holds for addressing the pandemic at different levels. The rapid identification and isolation of symptomatic adult patients within the community has become the cornerstone of controlling the recent outbreak. 2 Real-time quantitative polymerase chain reaction (PCR) is commonly used to confirm the diagnosis of COVID-19 and is considered the gold standard due to its high sensitivity and specificity. 3 Nevertheless, PCR is labor intensive and time consuming, requires skilled personnel with high cost, and is not available in remote settings.
Antigen tests emerged to address such drawbacks, offering rapid results, an easy-to-use procedure, diagnostic focus, and low costs. 4 In order to prepare against the next season winter, Moroccan's Government decided to introduce rapid antigen test to diagnose COVID-19

| Study type and population
This is a prospective observational prevalence study conducted at the Temara-Skhirat center in Morocco during mid-September 2021.

| Inclusion criteria
The patients included in this study were volunteers, having signed an informed consent before inclusion, aged between 18 and 65 years old, symptomatic (general, respiratory, and digestive signs), referred after consultation, and who have performed the rapid antigen test as well as the PCR.

| Exclusion criteria
The age groups below 18 and above 65 years of patients were excluded. Asymptomatic patients, contact cases, and seriously ill were also excluded from the study. Inconclusive results and patients who had not benefited from the rapid test as well as the PCR were excluded.

| Sampling
The sample was calculated depending on the flow of patients and the national prevalence finds in literature during this period time (about 2 weeks).
The calculation of the sample size was based on the following: Let n be the sample size, p the expected prevalence, e the margin of error at 4% (standard value of 0.04), and t the 95% confidence level (typical value of 1.96). Formula (1) is used to calculate the sample size. 6 The prevalence of COVID-19 in adults during this pandemic was made through daily data from the Ministry of Health and with fluctuations due to various factors related to the virus and human behavior.
Thus, using this formula, for an expected prevalence of 15%, the number of subjects to be recruited would be approximately 280 subjects.
In our study, we performed the rapid test in 206 participants whose plasma was tested with PCR for confirmation.

| Data collection
This study was carried out with the authorization of the regional directorate of the Ministry of Health of Rabat-Salé-Kenitra, which set up a screening system in a reference center by providing validated PANBIOS ® rapid tests and PCR tests in real time.

| Statistical analysis
A descriptive analysis of the validated data was conducted. Variables were expressed as counts, percentages, means and standard deviations, and medians with interquartile ranges, as appropriate. We performed univariate analysis using parametric and/or non-parametric statistical tests, as appropriate. We assessed sensitivity and specificity of the PANBIOS ® and PCR tests. A p-value less than 0.05 was considered statistically significant.
JAMOVI version 1.6 software was used in this statistical analysis.

| Ethical considerations
The ethical authorization of the study protocol was obtained from the An information letter and informed consent was also attached to the study protocol.

| RESULTS
Of a total of 206 participants (Figure 1), the mean age was 38 years ± 12 standard deviation, and the majority were women (59%).
The predominant marital status and occupation were married (60%) and unemployed (44%). Most of the participants had a higher level of education (53%) and an income below 3000 MAD (54%) (  To our knowledge, this is the first study to be carried out at the regional level in Morocco. The results show that the vaccination rate during the study was around 80%. 8 The results showed that in a symptomatic adult population of 206 patients, there were 49 positive samples or prevalence of 24% using the rapid PANBIOS ® test, which is close to the prevalence of the PCR test with 60 positive tests or 30% found in our study, making the PANBIOS ® rapid test reliable and effective for community-wide study as a prevalence guidance tool. 9 Studies have revealed that the rapid PANBIOS ® test has high sensitivity as recommended by WHO, which estimates a criterion of greater than or equal to 80% for sensitivity and a specificity of 97%. 10 We found close results, that is, 69% sensitivity and 95% specificity; this difference can be explained by the selection of the population studied or the size of the sample. Indeed, several studies have made comparisons between symptomatic and asymptomatic groups with a larger population. 1,3 Others studies of

| CONCLUSION
The prevalence of COVID-19 remains high in Temara-Skhirat region, Morocco. The PANBIOS ® rapid test is a quick diagnostic orientation